JPH06249286A - Vibration restraining device for rotor - Google Patents

Abstract

PURPOSE:To prevent resonance phenomenon so as to reduce amplitude by providing electromagnets and displacement detectors meeting at right angles with each other and acting in the sectional radial direction in a roller rotating around a fixed shaft at high speed, and holding a balance condition between the fixed shaft and the roller. CONSTITUTION:A vibration restraining device is constituted of primary yokes 11, secondary yokes 12, coils 13, sensors 14, and a drive circuit. A voide (dx) is always controlled to be held at a reference value in X-axis direction by a feedback loop, a sensor 14x the drive circuit attraction by coils 133, 134 and coils 137, 138 the sensor 14x (displacement detection). Similar action is performed also in Y-axis direction, and a void (dy) is controlled to be held at a reference value by a feedback loop, a sensor 14y the drive circuit attraction by coils 131, 132 and 135, 136 the sensor 14y. Consequently, the natural vibration is generated in the shaft 1 by rotation of the roller 2, and even if the amplitude of the natural vibration reaches the peak, the amplitude can be restrained to be very small.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing device for a rotating body suitable for use in, for example, a high speed electric motor of a textile machine.

[0001]

2. Description of the Related Art The structure of a conventional general electric motor, in particular, a high speed electric motor used in a textile machine will be described with reference to FIG. In the electric motor shown in this figure, a substantially hollow cylindrical roller 2 rotates with respect to a shaft 1 having both ends fixed,
That is the outer rotor motor. The roller 2 is rotatably attached to the shaft 1 via bearings 3 on both end surfaces thereof. A rotor core 5 is attached to the inner peripheral surface of the roller 2 via a magnet 4, while a stator core 6 is fixed to the shaft 1 so as to face the rotor core 4 and a gap. A rotating magnetic field is generated in the stator core 6 by the current supply of a cable 7 drawn through a hollow portion provided at one end of the shaft 1.

That is, the magnet 4, the rotor core 5, and the stator core 6 constitute an induction synchronous motor (the induction motor may be adopted as the motor in some cases) so that the roller 2 rotates with respect to the shaft 1. It has become. Then, by pressing the outer peripheral surface of the rotating roller 2 against the bobbin, for example,
It is configured to wind up a thread. Therefore, according to such a configuration, the peripheral speed of the rotating roller 2 is
It is almost proportional to the winding speed of the yarn.

On the other hand, recently, there is a demand for increasing the winding speed of the yarn in order to improve the productivity, and therefore, the roller 2 is required to have a high peripheral speed. For example, the peripheral speed of the roller 2 needs to be about 6,000 [m / min]. This includes
There are the following two approaches. That is, it is a method of increasing the outer diameter of the roller 2 or increasing the rotation speed of the roller 2. In the above method, not only the problem that the roller 2 itself becomes large, but also the bearing 3
There is a possible problem that accuracy is required to cope with this increase in weight. Therefore, conventionally, the method (1) has been used and the diameter of the shaft 1 has been made small so that the bearing 3 having a small maximum load and a small inner / outer diameter can be used.

[0004]

However, as the diameter of the shaft 1 becomes smaller, the frequency of the natural vibration generated in the shaft 1 decreases, and the natural vibration becomes
Along with the high rotation speed of the roller 2, there is a problem that the rotation speed is lower than the rotation speed that satisfies the above peripheral speed. Here, the natural vibration will be described. In general, the natural vibration represents a unique mechanical characteristic of the structure, and when the structure is excited at a natural frequency, a resonance phenomenon occurs and the structure vibrates with a very large amplitude. To do.

FIG. 8 shows the natural vibration of the shaft 1 and
The vibration mode is shown. Since the roller 2 has much higher rigidity than the shaft 1, the natural frequency of the roller 2 is also much higher than that of the shaft 1. Therefore, when looking at the entire electric motor, the natural vibration of the roller 2 can be ignored, and only the natural vibration of the shaft 1 can be considered. As shown in this figure, the shaft 1 naturally does not generate any vibration when the rotation of the roller 2 is stopped. However, when the roller 2 starts to rotate, the shaft 1 is excited by the vibration accompanying the rotation, and when the number of rotations of the roller 2 reaches 7,980 [rpm] (in this example), the shaft 1
Causes natural vibration (a frequency of 133 Hz in this example) having fixed points at both ends as “nodes” (first-order vibration mode).
In this case, the roller 2 vibrates in the vertical direction as a whole according to the vibration of the shaft 1.

Further, when the rotation speed of the roller 2 rises and reaches 16,080 [rpm], the shaft 1 is provided with a fixed point at both ends and a bisecting point (that is, a middle point) of the shaft 1. Natural frequency (frequency 268 Hz in this example)
Occurs (secondary vibration mode). In this case, the roller 2
With the vibration of the shaft 1, both ends of the roller 2 vibrate in opposite phases to each other, and thus vibrate in a seesaw manner. Similarly, as the roller 2 rises in rotation, the shaft 1 sequentially undergoes natural vibrations having "nodes" at the fixed points at both ends thereof and the n equally divided points thereof (nth order vibration mode). However, n is an integer greater than or equal to “1”, and as n becomes higher order, the natural vibration of the elements other than the shaft 1 cannot be ignored.

In this way, when the natural vibration is generated in the shaft 1 and the roller 2 vibrates accordingly, the vibration is propagated to the bobbin bobbin in the textile machine and the quality of the yarn is deteriorated. It was Further, due to the natural vibration, the rotor core 5 and the stator core 6 (see FIG. 7)
However, there is also a problem in that the motors may come into contact with each other, resulting in damage to the electric motor itself. The present invention has been made in view of the above-described problems, and an object thereof is to provide a vibration suppressing device for a rotating body capable of significantly reducing the amplitude of natural vibration associated with rotation.

[0008]

In order to solve the above-mentioned problems, the present invention is a rotary surface of a rotating body which is rotatable with respect to a fixed support shaft and which has two different rotating surfaces passing through the center of rotation of the rotating body. The first set and the second set of electromagnets that respectively attract the rotating body in the axial directions opposite to each other in the axial direction, and the displacement amounts of the fixed support shaft and the rotating body with respect to the reference value are set to the two different axes. First to detect in each direction
A second detecting means, and based on the displacement amount corresponding to the axial direction, one of the attraction forces by the electromagnets of the group corresponding to the axial direction is added, while the attraction force by the electromagnets of the same group is added. The subtraction of the other is performed for the first and second electromagnets according to the first and second detection means, respectively.

[0009]

According to the present invention, the displacement amounts of the fixed support shaft and the rotating body with respect to the reference value in the two different axial directions passing through the center of rotation of the rotating surface are detected by the first and second detecting means, respectively. To be done. Here, when the amount of displacement detected by the first detection means increases, one of the electromagnets of the first set is
In the direction of canceling out the increase in the displacement amount, the attraction force to the rotating body is increased, while the other electromagnets of the same group reduce the attraction force to the rotating body, so the rotating body and the fixed support shaft are
They are attracted to each other so that their increase in displacement is reduced. The same applies to the second detection means and the second set of electromagnets. As a result, the displacement amount between the fixed support shaft and the rotating body is always kept at the reference value. If the displacement amounts detected by the first and second detecting means are reference values,
The attraction force by the electromagnets of the first set and the second set is constant, and the supporting shaft and the rotating body are kept in equilibrium.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a side end view showing a schematic configuration of this embodiment. In this figure, the vibration suppressing device 10 of this embodiment is added to FIG. 7, and the vibration suppressing device 10 includes a primary yoke 11, a secondary yoke 12, a coil 13, a sensor 14, and a drive circuit 15. Composed of. In FIG. 1, the same parts as those in FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted.

Next, the detailed structure of this embodiment will be described. FIG. 2 is an end view taken along the line AA ′ in FIG.
As shown in this figure, a primary yoke 11 having radially arranged magnetic poles 11 _{1 to} 11 ₈ is attached to a shaft 1, and coils 13 _{1 to} 13 ₈ are respectively wound around these magnetic poles. There is. In these coils, the coils 13 ₁ ,
13 ₂ are electrically connected in series or in parallel, and similarly, the coils 13 ₃ and 13 ₄ and 13 ₅ and 13 ₆ are 1
3 ₇ and 13 ₈ are electrically connected in series or in parallel, respectively.

On the other hand, the magnetic pole 11 ₁ is formed on the inner peripheral surface of the roller 2.
Opposed to the secondary yoke 12 is attached to to 11 _8. The secondary yoke 12 may be omitted if the roller 2 is a magnetic body. Further, when the eddy current loss becomes a problem, the eddy current loss can be reduced by forming the primary yoke 11 and the secondary yoke into a laminated structure. Then, by passing a current through the coils 13 _{1 to} 13 ₈ , an electromagnetic force forming the magnetic force lines shown in the figure, that is, an attractive force to the secondary yoke 12, is applied to the magnetic poles 11 _{1 to} 11 ₈ and the secondary yoke 12. It is supposed to occur.

The sensor 14x detects how much the gap dx between the primary yoke 11 and the secondary yoke 12 is displaced with respect to the reference value in the x-axis direction shown in the drawing together with the displacement direction. For example, the sensor 14x outputs the displacement amount with a sign (-) when the gap is displaced in the smaller direction, and outputs the displacement amount with a sign (+) when the gap dx is displaced in the larger direction. ) To output. Similarly, the sensor 14y includes a primary yoke 11 and a secondary yoke 1.
How much the gap dy with 2 is displaced in the y-axis direction shown in the figure with respect to the reference value is detected together with the displacement direction.

Next, the electrical construction of this embodiment, particularly the sensors 14x and 14y, the drive circuit 15 and the coil 13 _1.
To 13 ₈ will be described with reference to FIG. 3. In this figure, the same parts as those in FIG. 2 are designated by the same reference numerals. As shown in this figure, the detection result of the sensor 14x is
It is supplied to the controller 153 via a predetermined amplification by the sensor amplifier 151. The controller 153 performs appropriate arithmetic processing on the detection result of the sensor 14x, for example, PID (proportional, integral, differential) arithmetic processing. Then, the controller 153 the result of the calculation, one input terminal of the adder 155 ₁ (+) and one input of the adder 155 ₂ - supplying the (). Adder 15
A constant current command C is supplied to the other input terminals of 5 ₁ and 155 ₂ .

In the adder 155 ₁ , this constant current command C
And the calculation result of the controller 153 are added, and the addition result is supplied to the coils 13 ₃ and 13 ₄ through the current amplification by the power amplifier 157 ₁ . On the other hand, the adder 155 _1, controller from the constant current command C 153
Is subtracted, and the subtraction result is passed through the current amplification by the power amplifier 157 ₂ to the coils 13 ₇ , 1
3 ₈ is supplied. The power amplifiers 157 ₁ and 157
The current amplification factors in ₂ are set equal to each other.

Similarly, the detection result of the sensor 14y is processed in the same manner as the sensor 14x. That is, the detection result of the sensor 14y is sequentially added to the constant current command C in the adder 156 ₁ through the amplification by the sensor amplifier 152 and the PID calculation by the controller 154, and the addition result is the current amplification by the power amplifier 158 _1. While being supplied to the coils 13 ₁ and 13 ₂ via the adder 156
₂ , the calculation result of the controller 154 is subtracted from the constant current command C, and the subtraction result is the power amplifier 158.
It is supplied to the coils 13 ₅ and 13 ₆ via the current amplification by ₂ .

Next, the operation of this embodiment will be described. When the rotation of the roller 2 is stopped or when the vibration associated with the rotation is extremely small, the primary yoke 11
Since the air gaps dx and dy of the secondary yoke 12 are reference values, respectively, the detection results of the sensors 14x and 14y are both “zero”. Therefore, the controllers 153 and 154 are provided.
The calculation result of is also "zero". Therefore, the adder 155
Result of addition by ₁ , 156 ₁ and adder 156 ₂ , 15
Since the subtraction result by 6 ₂ is only the constant current command C, the coils 13 ₁ , 13 ₂ , 13 ₃ , 13 ₄ and 1
The current values supplied to 3 ₅ , 13 ₆ and 13 ₇ , 13 ₈ are
Each will be the same. As a result, the coils 13 ₁ , 13
_The attraction forces exerted on the secondary yoke 12 by 2 and 13 ₅ , 13 ₆ cancel each other out, and similarly, the coils 13 ₃ , 1
The attraction forces on the secondary yoke 12 by 3 ₄ , 13 ₇ and 13 ₈ also cancel each other out. That is, the attraction force to the secondary yoke 12 by each coil is the x direction in FIG.
Since the y direction is balanced, the gaps dx and dy are maintained at the reference values.

Next, the shaft 1 is rotated by the rotation of the roller 2.
Will be described, and a case where a displacement occurs in the direction in which the air gap dx increases will be described. In this case, the sensor 14x is
Since the displacement amount with respect to the reference value is output as a sign (+),
The calculation result of the controller 153 also follows this. Thus, since the signal obtained by adding the calculation result is output to the adder 155 _1, a constant current command C, the coil 1
While the suction force generated by 3 ₃ and 13 ₄ increases, the adder 155 ₂ changes the constant current command C from the controller 15
Since the calculation result by 3 is reduced, the coils 13 ₇ , 1
The suction force generated by 3 ₈ is reduced. Since the rigidity of the roller 2 is higher than that of the shaft 1, the primary yoke 111 is relatively attracted to the (+) direction (to the right) of the x-axis, and as a result, the shaft 1 has a suction force that cancels the displacement. That is, the suction force acts in the direction of reducing the gap dx.

On the contrary, when the shaft 1 is excited by the rotation of the roller 2 and the displacement in the direction in which the gap dx becomes smaller occurs, the displacement amount with respect to the reference value is a sign (-).
Therefore, the adder 155 ₁ outputs a signal obtained by subtracting the calculation result of the controller 153 from the constant current command C, and the suction force generated by the coils 13 ₃ and 13 ₄ decreases, while the adder 155 ₂ Then, the constant current command C
And the calculation result of the controller 153 are added, the attraction force generated by the coils 13 ₇ and 13 ₈ increases. As a result, the primary yoke 1 is relatively attracted in the (−) direction (to the right) of the x-axis, so that the shaft 1 has a suction force that cancels the displacement, that is, a suction force that increases the gap dx. Works.

That is, in the x-axis direction, the sensor 14x →
Drive circuit 15 → coils 13 ₃ and 13 ₄ and coils 13 ₇ and 1
By 3 ₈ and by the suction → sensor 14x (displacement detection) of the feedback loop is controlled so that the air gap dx is always kept to the reference value. A similar operation is performed in the y-axis direction. That is, the feedback loop of the sensor 14y → the driving circuit 15 → the suction by the coils 13 ₁ and 13 ₂ and the coils 13 ₅ and 13 ₆ → the sensor 14y (displacement detection) is controlled so that the gap dy is always kept at the reference value. To be done. Therefore, by independently controlling the displacements in the x-axis and y-axis directions, the air gaps dx and dy between the primary yoke 11 and the secondary yoke 12 are always kept at the reference values over the entire area of the rotation surface in FIG. Therefore, even if natural vibration occurs in the shaft 1 due to the excitation by the rotation of the roller 2 and the amplitude of the natural vibration reaches a peak, the amplitude can be suppressed to be extremely small.

FIG. 4 is a characteristic diagram showing the relationship between the rotation speed of the roller 2 and the vibration amplitude at point a (one end of the outer peripheral surface of the roller 2 in FIG. 8). As shown in this figure, in the conventional example,
Natural vibrations are sequentially generated as the number of rotations of the roller 2 increases, so that the amplitude at the point a at one end of the outer peripheral portion sequentially peaks at the number of rotations of 7,980 [rpm] and 16,080 [rpm]. On the other hand, in the electric motor to which this embodiment is added, natural vibration is generated as the number of rotations of the roller 2 is increased, as in the conventional example, but it is suppressed to a very small value even when the amplitude reaches its peak. I understand. Therefore,
According to the electric motor loaded with this embodiment, it is possible to reduce the vibration over the entire range up to the substantially maximum rotation speed. It is possible to use numbers.

In this embodiment, the installation location of the primary yoke 11 and the secondary yoke 12 was not particularly described, but
Regarding the natural vibration of the shaft 1, it is obvious that the vibration suppressing effect is most effective if the vibration suppressing device according to the present invention is installed in the "antinode" portion of the vibration mode to be suppressed. In addition, since this embodiment is configured to be incorporated inside the electric motor, it requires little space outside.

In this embodiment, the same constant current command C is added to or subtracted from the calculation result according to the displacement amount in each axial direction.
In the case where the roller 2 is pressed against the external device in the x-axis direction, the coils facing each other in the x-axis direction, that is, the coils 13 ₃ and 13 ₄ and the coils 13 ₇ and 13 ₈ are formed. The constant current command C and the addition result of adding the current command C ′ indicating the pressing pressure of the roller 2 to the constant current command C may be added to or subtracted from the calculation result of the displacement amount by the sensor 14x, respectively. . As a result, the pressing pressure is offset in advance, so that the load on the bearing 3 can be reduced even when the outer peripheral surface of the roller 2 is pressed against the bobbin.
Alternatively, the spring constant when pressed can be changed arbitrarily.

In the above embodiment, the x-axis direction and y
Each sensor was used to detect the displacement in the axial direction. However, as shown in FIG.
Sensors 14 'facing each other at symmetrical positions of x and 14y
x, 14′y may be provided, and the difference between the detection results of these facing sensors may be obtained by the differential amplifiers 159, 160 and supplied to the sensor amplifiers 151, 152. With this configuration, not only the detection sensitivity of the displacement amount is doubled, but also the noise peculiar to the sensor, the characteristic change due to the temperature change, and the like can be canceled, so that the measurement accuracy can be improved.

[0025]

According to the present invention described above, when the displacement amount detected by the first or second detecting means increases, one of the electromagnets of the first set or the second set increases the displacement amount. While the attraction force to the rotating body is increased so as to cancel out, the other of the electromagnets in the same group reduces the attraction force to the rotating body, so that the displacement amount between the rotating body and the fixed support shaft increases. To be reduced, they are sucked together. Therefore, even if the natural vibration caused by the rotation occurs, the displacement amount between the fixed support shaft and the rotating body is always kept at the reference value.
Since the attractive force is increased or decreased, the natural vibration can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a side end view showing a configuration of a main part of a first embodiment according to the present invention.

FIG. 2 is an end view taken along the line A-A ′ in FIG.

FIG. 3 is a block diagram showing an electrical configuration of the embodiment.

FIG. 4 is a characteristic diagram showing the relationship between the rotation speed of the roller 2 and the vibration amplitude in the same example.

FIG. 5 is a block diagram showing an electrical configuration of a second embodiment according to the present invention.

FIG. 6 is a block diagram showing an electrical configuration of a third embodiment according to the present invention.

FIG. 7 is a side end view showing the structure of a high-speed electric motor used in a conventional textile machine.

FIG. 8 is an explanatory diagram showing a natural vibration of the shaft 1 and its vibration mode.

[Explanation of symbols]

1 ... Shaft (fixed support shaft), 2 ... Roller (rotating body), 11 ₃ , 11 ₄ ...... Magnetic pole, 13 ₃ , 13 ₄ ...... Coil, 11 ₇ , 11 ₈ ...... Magnetic pole, 13 ₇ , 13 ₈ …… Coil (first set of electromagnets), 11 ₁ , 11 ₂ …… Magnetic pole, 13 ₁ ,
13 ₂ ... coil, 11 ₅ , 11 ₆ ... magnetic pole, 13 ₅ , 13
₆ ... Coil (second set of electromagnets), 14x ... Sensor (first detection means), 14y ... Sensor (second detection means)

Claims (1)

[Claims] 1. A rotating surface of a rotating body rotatable with respect to a fixed support shaft, wherein the rotating body is sucked in two different axial directions passing through the center of rotation of the rotating body in opposite axial directions. The first and second sets of electromagnets, and the displacement amounts of the fixed support shaft and the rotating body with respect to the reference value are respectively detected in the two different axial directions.
A second detection means, and based on the displacement amount corresponding to the axial direction, one of the attraction forces by the electromagnets of the group corresponding to the axial direction is added, while the attraction force by the electromagnets of the same group is added. A vibration suppressing device for a rotating body, wherein the other is subtracted from the first and second electromagnets according to the first and second detecting means, respectively.